Femoral orthopaedic instrument assembly for setting offset

ABSTRACT

A number of orthopaedic surgical instruments for use in a surgical procedure to prepare a patient&#39;s femur to receive an orthopedic prosthesis. The tools include guide tools, cutting tools, surgical blocks, and other orthopaedic surgical instruments configured to plan and guide the preparation of the patient&#39;s femur. A method of using the orthopaedic surgical instruments is also disclosed.

CROSS-REFERENCE

Cross reference is made to U.S. patent application Ser. No. 13/832,203,now U.S. Pat. No. 9,232,950, and U.S. patent application Ser. No.13/832,183, now U.S. Pat. No. 9,282,981; each of which is assigned tothe same assignee as the present application, each of which has the samepriority date as the present application, and each of which is herebyincorporated by reference.

This application is a divisional of U.S. patent application Ser. No.15/584,654, now U.S. Pat. No. 10,413,307, which is continuation of U.S.patent application Ser. No. 13/832,194, now U.S. Pat. No. 9,636,122;each of which is herein incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic instruments foruse in the performance of an orthopaedic joint replacement procedure,and more particularly to orthopaedic surgical instruments for use in theperformance of a knee replacement procedure.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a total knee arthroplasty surgical procedure, apatient's natural knee joint is partially or totally replaced by aprosthetic knee joint or knee prosthesis. A typical knee prosthesisincludes a tibial tray, a femoral component, and a polymer insert orbearing positioned between the tibial tray and the femoral component.The tibial tray generally includes a plate having a stem extendingdistally therefrom, and the femoral component generally includes a pairof spaced apart condylar elements, which include surfaces thatarticulate with corresponding surfaces of the polymer bearing. The stemof the tibial tray is configured to be implanted in asurgically-prepared medullary canal of the patient's tibia, and thefemoral component is configured to be coupled to a surgically-prepareddistal end of a patient's femur

From time-to-time, a revision knee surgery may need to be performed on apatient. In such a revision knee surgery, the previously-implanted kneeprosthesis is surgically removed and a replacement knee prosthesis isimplanted. In some revision knee surgeries, all of the components of thepreviously-implanted knee prosthesis, including, for example, the tibialtray, the femoral component, and the polymer bearing, may be surgicallyremoved. In other revision knee surgeries, only part of thepreviously-implanted knee prosthesis may be removed and replaced.

During a revision knee surgery, the orthopaedic surgeon typically uses avariety of different orthopaedic surgical instruments such as, forexample, cutting blocks, surgical reamers, drill guides, prosthetictrials, and other surgical instruments to prepare the patient's bones toreceive the knee prosthesis. Other orthopaedic surgical instruments suchas trial components may be used to size and select the components of theknee prosthesis that will replace the patient's natural joint. Trialcomponents may include a femoral trial that may be used to size andselect a prosthetic femoral component, a tibial tray trial that may beused to size and select a prosthetic tibial tray, and a stem trial thatmay be used to size and select a prosthetic stem component.

SUMMARY

According to one aspect of the disclosure, a method of surgicallypreparing a patient's femur to receive an orthopaedic prosthesis isdisclosed. The method includes attaching a stem trial to a proximal endof an offset tool, advancing the stem trial through a distal surface ofthe patient's femur into a distal end of a medullary canal, positioninga surgical block on a distal surface of the patient's femur, attachingthe surgical block to a distal end of the offset tool, rotating thedistal end of the offset tool relative to the stem trial to move thesurgical block on the distal surface of the patient's femur, andpreventing rotation of the distal end of the offset tool when thesurgical block is in a desired offset orientation, advancing acannulated reamer over the distal end of the offset tool. The methodalso includes reaming the patient's femur with the cannulated reamer todefine a chamber at the distal end of the medullary canal, removing thestem trial from the medullary canal, and inserting an intramedullaryorthopaedic surgical instrument into the chamber and the medullary canalof the patient's femur. The intramedullary orthopaedic surgicalinstrument includes the stem trial.

In some embodiments, attaching the surgical block to the distal end ofthe offset tool may include advancing a guide block over the distal endof the offset tool, and positioning a locking pin of the guide block ina slot defined in the surgical block. Additionally, attaching thesurgical block to the distal end of the offset tool may include rotatinga tab of the surgical block into a channel defined in the mountingbracket of the guide block.

In some embodiments, the method may include selecting a first slot of aplurality of slots defined in the distal end of the offset tool. Eachslot may correspond to a desired reaming depth. The method may alsoinclude engaging the first slot with a locking tab of the guide block.

In some embodiments, reaming the patient's femur with the cannulatedreamer may include identifying a depth indicator on the cannulatedreamer corresponding to the desired reaming depth, and advancing thecannulated reamer into the patient's femur until the depth indicator iscoplanar with the distal surface of the patient's femur.

In some embodiments, the method may include attaching a handle to thedistal end of the offset tool after attaching the surgical block to theoffset tool, and rotating the distal end of the offset tool may includegripping the handle to rotate the distal end of the offset tool.

In some embodiments, preventing rotation of the distal end of the offsettool may include engaging a connecting shaft that is moveably coupled tothe handle, and rotating the connecting shaft relative to the handle tooperate a locking mechanism of the offset tool.

In some embodiments, the method may include securing the intramedullaryorthopaedic surgical instrument to an intramedullary adaptor,positioning a first adaptor body of the intramedullary adaptor relativeto a second adaptor body of the intramedullary adaptor based on thedesired offset orientation, and locking the first adaptor body inposition relative to the second adaptor body.

Additionally, the method may include identifying a first offsetindicator when the surgical block is in the desired offset orientation.The first offset indicator may correspond to the desired offsetorientation. The method may also include identifying a second offsetindicator on the intramedullary adaptor corresponding to the desiredoffset orientation, and positioning the first adaptor body of theintramedullary adaptor relative to the second adaptor body of theintramedullary adaptor based on the desired offset orientation mayinclude rotating the first adaptor body of the intramedullary adaptorrelative to the second adaptor body to a position associated with thesecond offset indicator.

In some embodiments, securing the intramedullary orthopaedic surgicalinstrument to the intramedullary adaptor may include securing a distalend of the stem trial to a proximal end of a stem stabilizer andsecuring the distal end of the stem stabilizer to a proximal end of theintramedullary adaptor.

In some embodiments, the method may include positioning a mountingbracket of the intramedullary adaptor in a slot defined the surgicalblock, and advancing a tab of the surgical block into a channel definedin the mounting bracket to secure the intramedullary adaptor to thesurgical block. Additionally, the method may include operating a lockingmechanism of the intramedullary adaptor to permit the mounting bracketto rotate relative to the first adaptor body, and rotating the mountingbracket and the surgical block on the distal surface of the patient'sfemur relative to the first adaptor body. In some embodiments, thesurgical block used in the method may include a cutting guide slotconfigured to guide a surgical saw during a resection of a posteriorsurface of the patient's femur.

According to another aspect, a method for performing an orthopaedicsurgical procedure on a patient's femur includes securing a distal endof an intramedullary orthopaedic surgical instrument to a proximal endof an intramedullary adaptor, rotating a first adaptor body of theintramedullary adaptor to a desired offset orientation relative to asecond adaptor body of the intramedullary adaptor, advancing theintramedullary orthopaedic surgical instrument and the proximal end ofthe intramedullary adaptor through a distal surface of the femur, andpositioning a surgical block secured to the distal end of theintramedullary adaptor on the distal surface of the femur.

In some embodiments, the method may include positioning a mountingbracket of the intramedullary adaptor in a slot defined the surgicalblock and advancing a tab of the surgical block into a channel definedin the mounting bracket to secure the intramedullary adaptor to thesurgical block.

In some embodiments, the surgical block may include a cutting guide slotconfigured to guide a surgical saw during a resection of a posteriorsurface of the patient's femur.

In some embodiments, the method may include attaching a stem trial to aproximal end of an offset tool, advancing the stem trial and theproximal end of the offset tool through the distal surface of thepatient's femur into a distal end of a medullary canal, and rotating adistal end of the offset tool relative to the stem trial to identify thedesired offset orientation.

In some embodiments, the method may include advancing a cannulatedreamer over the distal end of the offset tool when the distal end ispositioned in the desired offset orientation, and reaming the patient'sfemur with the cannulated reamer.

According to another aspect, a method for performing an orthopaedicsurgical procedure on a patient's femur includes positioning anintramedullary orthopaedic surgical instrument in a medullary canal ofthe patient's femur, positioning a reamer guide assembly on a distalsurface of the patient's femur in a desired offset orientation relativeto the intramedullary orthopaedic surgical instrument, advancing acannulated reamer over a shaft of the reamer guide assembly to ream thepatient's femur at the desired offset orientation, removing theintramedullary orthopaedic surgical instrument from the medullary canalof the patient's femur after reaming, and securing the intramedullaryorthopaedic surgical instrument to a proximal end of an intramedullaryadaptor. The method also includes positioning a first adaptor body ofthe intramedullary adaptor relative to a second adaptor body of theintramedullary adaptor based on the desired offset orientation,inserting the intramedullary orthopaedic surgical instrument and theproximal end of the intramedullary adaptor into the patient's femur, andoperating a locking mechanism to permit a distal end of theintramedullary adaptor to rotate relative to the first adaptor body.

In some embodiments, positioning the reamer guide assembly on the distalsurface of the patient's femur may include locating a surgical blockthat includes a cutting guide slot configured to guide a surgical sawduring a resection of a posterior surface of the patient's femur on thedistal surface in the desired offset orientation, and inserting theintramedullary orthopaedic surgical instrument and the proximal end ofthe intramedullary adaptor into the patient's femur may include locatingthe surgical block on the distal surface in the desired offsetorientation. The surgical block may be secured to the distal end of theintramedullary adaptor.

According to one aspect of the disclosure, an orthopaedic surgicalinstrument assembly is disclosed. The instrument assembly includes acutting block including a base plate and a pair of curved arms extendingposteriorly from the base plate. Each curved arm includes a posteriorsurface and a cutting guide defined in the posterior surface. Theinstrument assembly also includes a stem trial positioned proximal tothe base plate of the cutting block, and an offset tool having aproximal end coupled to the stem trial and a distal end coupled to thecutting block. The proximal end of the offset tool defines a first axis,and the distal end of the offset tool defines a second axis extendingparallel to the first axis. The proximal end of the offset tool isconfigured to pivot relative to the distal end.

In some embodiments, the instrument assembly may include a guide blockincluding a mounting bracket engaged with the base plate. The offsettool may include a shaft extending through a cylindrical passagewaydefined in the guide block. Additionally, the cutting block may includea tab that is pivotal between a first position in which the tab isengaged with the mounting bracket to secure the guide block to thecutting block, and a second position in which the tab is disengaged fromthe mounting bracket such that the guide block is removable from thecutting block.

In some embodiments, the guide block may include a locking mechanismconfigured to secure the guide block to the shaft of the offset tool. Insome embodiments, the shaft of the offset tool may include a pluralityof slots. Each slot may correspond to a predetermined reaming depth, andthe locking mechanism of the guide block may include a locking pin thatis moveable between a first position in which the locking pin ispositioned in one of the plurality of slots to secure the guide block tothe shaft of the offset tool, and a second position in which the lockingpin is disengaged from the plurality of slots such that the guide blockis removable from the shaft.

Additionally, in some embodiments, the offset tool may include a lockingmechanism configured to prevent rotation of the distal end relative tothe proximal end. The shaft of the offset tool may be a first shaftincluding the proximal end of the offset tool, and the offset tool mayinclude a connecting body extending between the first shaft and a secondshaft. The second shaft may include the distal end of the offset tool.The locking mechanism may include a threaded rod positioned in apassageway defined in the first shaft. The threaded rod may be moveablealong the first axis between a first position in which the threaded rodis spaced apart from the connecting body such that relative movementbetween the first shaft and the second shaft is permitted, and a secondposition in the threaded rod is engaged with the connecting body suchthat relative movement between the first shaft and the second shaft isprevented.

In some embodiments, the instrument assembly may further include ahandle engaged with the distal end of the first shaft. A connecting rodmay be pivotally coupled to the handle, and the connecting rod may havea driver head configured to be engaged with a distal end of the threadedrod. In some embodiments, the handle may include a plurality of internalthreads that engage a plurality of external threads formed on the distalend of the shaft.

In some embodiments, the instrument assembly may further include anindicator to indicate a position of the proximal end relative to thedistal end of the offset tool. Additionally, in some embodiments, theinstrument assembly may further include a cannulated reamer sized toreceive a shaft of the offset tool.

According to another aspect, an orthopaedic surgical instrument assemblyincludes a surgical block having a proximal surface, a distal surfaceopposite the proximal surface, and a slot extending through the proximalsurface and the distal surface. The instrument assembly also includes aguide block including a mounting bracket positioned in the slot andremovably coupled to the surgical block, an offset tool including afirst shaft that extends through a cylindrical passageway defined in theguide block and defines a first axis and a second shaft pivotallycoupled to the first shaft. A stem trial is secured to the second shaftof the offset tool. An oblique angle is defined between the first axisand an imaginary plane defined by the proximal surface of the surgicalblock.

In some embodiments, the instrument assembly may further include a rodcoupled to the first shaft. The rod may be moveable along the first axisbetween a first position in which the first shaft is permitted to rotaterelative to the second shaft and a second position in which the firstshaft is prevented from rotating relative to the second shaft.

In some embodiments, the instrument assembly may include a handlesecured to the first shaft, and a connecting rod moveably coupled to thehandle. The connecting rod may have a driver head engaged with a distalend of the rod.

In some embodiments, the surgical block may include a base plate havingthe slot defined therein and a pair of curved arms extending posteriorlyfrom the base plate. Each curved arm may include a posterior surface anda cutting guide defined in the posterior surface. In some embodiments,the instrument assembly may include a cannulated reamer including anaperture sized to receive a shaft of the offset tool.

In some embodiments, the first shaft of the offset tool may include aplurality of slots, and each slot may correspond to a predeterminedreaming depth of the cannulated reamer. The guide block may include alocking pin that is moveable between a first position in which thelocking pin is positioned in one of the plurality of slots to secure theguide block to the first shaft of the offset tool and a second positionin which the locking pin is disengaged from the plurality of slots suchthat the guide block is removable from the first shaft.

According to another aspect, an orthopaedic surgical instrument assemblyincludes an offset tool and a stem trial. The offset tool includes afirst shaft defining a first axis, a second shaft pivotally coupled tothe first shaft, and a locking mechanism configured to prevent relativemovement between the first shaft and the second shaft. The stem trial issecured to the second shaft of the offset tool. The stem trial includesan elongated body that defines a second axis extending parallel to thefirst axis. The instrument assembly also includes a cannulated reamerincluding an aperture sized to receive the first shaft of the offsettool.

In some embodiments, the offset tool may include a connecting bodyextending between the first shaft and the second shaft, and the lockingmechanism may include a rod coupled to the first shaft. The rod may bemoveable along the first axis between a first position in which a tip ofthe rod is spaced apart from the connecting body such that relativemovement between the first shaft and the second shaft is permitted and asecond position in which the tip is engaged with the connecting bodysuch that relative movement between the first shaft and the second shaftis prevented.

In some embodiments, the instrument assembly further includes a handlesecured the shaft, and a connecting shaft moveably coupled to thehandle. The connecting shaft may be operable to move the rod between thefirst position and the second position.

According to another aspect, an orthopaedic surgical instrument assemblyincludes a cutting block and an intramedullary orthopaedic surgicalinstrument. The cutting block includes a base plate, and a pair ofcurved arms extending posteriorly from the base plate. Each curved armincludes a posterior surface and a cutting guide defined in theposterior surface. The intramedullary orthopaedic surgical instrument isconfigured to be inserted into a medullary canal of a patient's femur.The instrument assembly also includes an adaptor positioned in a slotdefined in the base plate. The adaptor includes a mounting bracketengaged with the base plate, a first adaptor body coupled to themounting bracket, and a second adaptor body pivotally coupled to thefirst adaptor body. The second adaptor body includes a fastener coupledto the intramedullary orthopaedic surgical instrument. The first adaptorbody defines a first axis, the intramedullary orthopaedic surgicalinstrument includes an elongated body that defines a second axisextending parallel to the first axis, and when the second adaptor bodyis pivoted relative to the first adaptor body, the elongated body ispivoted about the first axis.

In some embodiments, the intramedullary orthopaedic surgical instrumentmay include a stem trial including the elongated body and anexternally-threaded end, and a stem stabilizer including a secondelongated body. The second elongated body has an internally-threadedfirst end engaged with the externally-threaded end of the stem trial andan internally-threaded second end positioned opposite the first end. Thesecond end may be engaged with a threaded shaft of the fastener of theadaptor.

In some embodiments, the mounting bracket may include a distal surfacethat defines an imaginary plane. An oblique angle may be defined betweenthe first axis of the first adaptor body and the imaginary plane.

In some embodiments, the adaptor may include a locking mechanismconfigured to prevent relative movement between the second adaptor bodyand the first adaptor body. Additionally, the locking mechanism mayinclude a threaded pin coupled to the first adaptor body. The threadedpin may be moveable between a first position in which a tip of thethreaded pin engages the second adaptor body to prevent relativemovement between the second adaptor body and the first adaptor body anda second position in which the tip of the threaded pin is disengagedfrom the second adaptor body to permit relative movement between thesecond adaptor body and the first adaptor body.

In some embodiments, the first adaptor body may have a passagewayextending along the first axis of the first adaptor body to a proximalend and an aperture defined at the proximal end. The threaded pin may bepositioned in the aperture.

In some embodiments, the mounting bracket may be pivotally coupled tothe first adaptor body, and the adaptor may include a locking mechanismconfigured to prevent relative movement between the mounting bracket andthe first adaptor body.

Additionally, in some embodiments, the locking mechanism may include athreaded insert attached to a distal end of the first adaptor body. Whenthe threaded insert is rotated in a first direction, an annular flangeof the first adaptor body may be moved along the first axis intoengagement with a proximal surface of the mounting bracket such thatrelative movement between the first adaptor body and the mountingbracket is prevented. When the threaded insert is rotated in a seconddirection, the annular flange of the first adaptor body may be movedalong the first axis away from the proximal surface of the mountingbracket such that relative movement between the first adaptor body andthe mounting bracket is permitted.

In some embodiments, the cutting block may include a tab pivotallycoupled to the base plate. The tab may be moveable between a firstposition in which the tab is engaged with the mounting bracket to securethe adaptor to the cutting block, and a second position in which the tabis disengaged from the mounting bracket such that the adaptor isremovable from the cutting block.

In some embodiments, the instrument assembly may include a guide blockconfigured to be positioned in the slot of the base plate in place ofthe adaptor. The guide block may include a mounting bracket configuredto engage with the cutting block and a cylindrical passageway definedtherein sized to receive an orthopaedic surgical instrument.

According to another aspect, an orthopaedic surgical instrument assemblyincludes a mounting bracket including a main housing and a pair of armsextending outwardly from the main housing. Each arm has a slot definedtherein sized to receive a locking tab of a surgical block. Theinstrument assembly also includes a first body pivotally coupled to aproximal end of the main housing of the mounting bracket. The first bodydefines a first longitudinal axis. A second body is pivotally coupled toa proximal end of the first body. The second body is configured to becoupled to an orthopaedic intramedullary adaptor and defines a secondlongitudinal axis extending parallel to the first longitudinal axis. Themounting bracket includes a distal surface that defines an imaginaryplane, and an oblique angle is defined between the imaginary plane andthe first longitudinal axis.

In some embodiments, the instrument assembly may include anintramedullary orthopaedic surgical instrument secured to a distal endof the second body. The intramedullary orthopaedic surgical instrumentmay include a stem trial configured to be inserted into a medullarycanal of a patient's femur.

In some embodiments, the stem trial may include an externally-threadeddistal end. The intramedullary orthopaedic surgical instrument mayinclude a stem stabilizer including an internally-threaded first endengaged with the externally-threaded distal end of the stem trial and aninternally-threaded second end positioned opposite the first end, thesecond end being engaged with an externally-threaded end of the secondbody.

In some embodiments, the instrument assembly may include a first lockingmechanism configured to prevent relative movement between the mountingbracket and the first body, and a second locking mechanism configured toprevent relative movement between the second body and the first body.

Additionally, the first body may have a threaded inner wall that definespassageway extending along the first longitudinal axis of the firstbody. The first locking mechanism may include an insert engaged with thethreaded inner wall of the first body. When the insert is rotated in afirst direction, an annular flange of the first body may be moved alongthe first longitudinal axis into engagement with a proximal surface ofthe mounting bracket such that relative movement between the first bodyand the mounting bracket is prevented. When the insert is rotated in asecond direction, the annular flange of the first body may be movedalong the first longitudinal axis away from the proximal surface of themounting bracket such that relative movement between the first body andthe mounting bracket is permitted.

In some embodiments, the first body may have an aperture positioned at aproximal end of the passageway, and the second locking mechanism mayinclude a threaded pin positioned in the aperture of the first body. Thethreaded pin may be moveable between a first position in which a tip ofthe threaded pin engages the second body to prevent relative movementbetween the second body and the first body and a second position inwhich the tip of the threaded pin is disengaged from the second body topermit relative movement between the second body and the first body.

In some embodiments, the insert of the first locking mechanism may havea passageway extending therethrough. The passageway may be sized topermit a surgical tool to extend through to engage the threaded pin.

According to another aspect, an orthopaedic surgical instrument systemincludes a surgical block including a locking tab, and an adaptorconfigured to be positioned in a slot defined in the surgical block. Theadaptor includes a mounting bracket configured to engage the locking tabto secure the adaptor to the surgical block, a first adaptor bodycoupled to the mounting bracket and defining a first axis, and a secondadaptor body pivotally coupled to the first adaptor body. The secondadaptor body defines a second axis offset from and extending parallel tothe first axis. The instrument system also includes an offset toolincluding a first shaft that defines a third axis and a second shaftpivotally coupled to the first shaft. The second shaft defines a fourthaxis offset from and extending parallel to the third axis. Theinstrument system includes a guide block configured to be positioned inthe slot of the surgical block in place of the adaptor. The guide blockincludes a mounting bracket configured to engage the locking tab tosecure the guide block to the surgical block and a cylindricalpassageway defined therein sized to receive the first shaft of theoffset tool. The second axis is offset from the first axis by a firstdistance, and the fourth axis offset from the third axis by a seconddistance equal to the first distance.

The surgical block may include a base plate having the slot definedtherein and a pair of curved arms extending posteriorly from the baseplate. Each curved arm may include a posterior surface and a cuttingguide defined in the posterior surface.

In some embodiments, the instrument system may include a stem trialincluding a first elongated body and an externally-threaded end, and astem stabilizer including a second elongated body. The second elongatedbody may have an internally-threaded first end configured to engage theexternally-threaded end of the stem trial and an internally-threadedsecond end positioned opposite the first end. The second end may beengaged with a distal end of the adaptor. The offset tool may have aninternally-threaded proximal end configured to engage theexternally-threaded end of the stem trial.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is an exploded perspective view of a cutting block and an offsetguide assembly of an orthopaedic surgical instrument system;

FIG. 2 is a plan view of the cutting block of FIG. 1;

FIG. 3 is an elevation view of the cutting block of FIGS. 1-2;

FIG. 4 is a perspective view of an offset guide tool of the offset guideassembly of FIG. 1;

FIG. 5 is an elevation view of the offset guide tool of FIG. 4;

FIG. 6 is a cross-sectional elevation view taken along the line 6-6 inFIG. 4 showing an unlocked position of the offset guide tool;

FIG. 7 is a view similar to FIG. 6 showing a locked position of theoffset guide tool;

FIG. 8 is an perspective view of a guide block of the offset guideassembly of FIG. 1;

FIG. 9 is an elevation view of the guide block of FIG. 8;

FIG. 10 is a cross-sectional elevation view of the guide block takenalong the line 10-10 in FIG. 8;

FIG. 11 is a perspective view of a handle assembly of the orthopaedicsurgical instrument system;

FIG. 12 is a cross-sectional elevation view of the handle assembly takenalong the line 12-12 in FIG. 11;

FIG. 13 is a perspective view of a surgical reamer of the orthopaedicsurgical instrument system;

FIG. 14 is an exploded perspective view of an orthopaedic surgicalinstrument construct of the orthopaedic surgical instrument system;

FIG. 15 is a perspective view of a stem stabilizer of the instrumentconstruct of FIG. 14;

FIG. 16 is a perspective view of an intramedullary adaptor of theinstrument construct of FIG. 14;

FIG. 17 is an elevation view of the intramedullary adaptor of FIG. 16;

FIG. 18 is an exploded elevation view of the intramedullary adaptor ofFIGS. 16-17;

FIG. 19 is a fragmentary, cross-sectional elevation view taken along theline 19-19 in FIG. 17 showing a distal locking mechanism of theintramedullary adaptor in an unlocked position;

FIG. 20 is a view similar to FIG. 19 showing the distal lockingmechanism of the intramedullary adaptor in a locked position;

FIG. 21 is a fragmentary, cross-sectional elevation view taken along theline 19-19 in FIG. 17 showing a proximal locking mechanism of theintramedullary adaptor in an unlocked position;

FIG. 22 is a view similar to FIG. 21 showing the proximal lockingmechanism of the intramedullary adaptor in a locked position;

FIG. 23 is a perspective view of a femoral orthopaedic prosthesis;

FIGS. 24-32 show the instruments of the orthopaedic surgical instrumentsystem being used to plan and guide the reaming of the distal end of thepatient's femur;

FIG. 33 is a plan view of the distal end of the patient's femurfollowing the reaming of the distal end of the patient's femur;

FIG. 34 is an elevation view of the patient's femur following thereaming of the distal end of the patient's femur; and

FIGS. 35-39 show the instruments of the orthopaedic surgical instrumentsystem being used to position the cutting block of FIG. 1 on the distalend of the patient's femur and intraoperatively evaluate the joint spaceof the patient's knee.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants andorthopaedic surgical instruments described herein as well as inreference to the patient's natural anatomy. Such terms havewell-understood meanings in both the study of anatomy and the field oforthopaedics. Use of such anatomical reference terms in the writtendescription and claims is intended to be consistent with theirwell-understood meanings unless noted otherwise.

Referring now to FIGS. 1-22, an orthopaedic surgical instrument system10 (hereinafter instrument system 10) is shown. What is meant herein bythe term “orthopaedic surgical instrument” or “orthopaedic surgicalinstrument system” is a surgical tool for use by a surgeon in performingan orthopaedic surgical procedure. As such, it should be appreciatedthat, as used herein, the terms “orthopaedic surgical instrument” and“orthopaedic surgical instruments” are distinct from orthopaedicimplants or prostheses that are surgically implanted in the body of thepatient. As described in greater detail below, the system 10 may be usedto plan and guide the reaming of a distal end 622 of a patient's femur620 (see FIG. 24) to receive an orthopaedic surgical instrumentconstruct 400. When positioned on the patient's femur, the instrumentconstruct 400 may be used to plan and guide the preparation of thedistal end of the patient's femur to receive a femoral orthopaedicprosthesis 650 (see FIG. 23), as described in greater detail below.

The instrument system 10 includes a base cutting block 12 configured foruse on a femur of a patient, and an offset guide assembly 14 configuredto be secured to the base cutting block 12. The system 10 also includesan intramedullary orthopaedic surgical instrument 16 configured to becoupled to the offset guide assembly 14. What is meant herein by theterm “intramedullary orthopaedic surgical instrument” is a surgical toolconfigured to be positioned in the medullary canal of the patient'sfemur during the orthopaedic surgical procedure. Examples ofintramedullary orthopaedic surgical instruments include femoral stemtrials, femoral broaches, and the like. As shown in FIG. 1, theintramedullary orthopaedic surgical instrument 16 includes a stem trial18, which may be used to size and select a prosthetic stem component.

The stem trial 18 includes an elongated body 20 that defines alongitudinal axis 22 extending through the distal end 24 and theproximal end 26. A plurality of external threads 28 are defined on thedistal end 24 of the stem trial 18. As described in greater detailbelow, the external threads 28 are configured to engage a plurality ofinternal threads 30 (see FIG. 4) formed on the offset guide assembly 14to secure the stem trial 18 to the assembly 14. In the illustrativeembodiment, the stem trial 18 is formed from a metallic material, suchas, for example, a stainless steel or a cobalt chromium alloy.

As described above, the instrument system 10 includes a base cuttingblock 12 configured for use on a femur of a patient. As shown in FIGS.1-3, the base cutting block 12 includes a base plate 40 and a pair ofarms 42 extending from the base plate 40. It should be appreciated thatin other embodiments the base cutting block 12 may have a differentconfiguration including, for example, only the base plate 40. The baseplate 40 and the arms 42 of the base cutting block 12 are formed from ametallic material, such as, for example, a stainless steel or a cobaltchromium alloy. The base plate 40 includes a distal surface 44 and aproximal surface 36 positioned opposite the distal surface 44. Anopening 48 is defined in the distal surface 44, and an inner wall 50extends distally through the base plate 40 to define a receiving slot52.

As shown in FIGS. 2-3, the base plate 40 of the base cutting block 12has a pair of side walls 54 that extend between the distal surface 44and the proximal surface 46. Each side wall 54 has an opening 56 definedtherein and a channel 60 extends inwardly from each opening 56. Eachchannel 60 is sized to receive a mounting shaft or pin from anothersurgical instrument such as, for example, a distal spacer block. Itshould be appreciated that in other embodiments the channels 60 may beomitted.

As shown in FIG. 2, the base cutting block 12 also includes a pair offastener guides 62 that are defined in the base plate 40. Each fastenerguide 62 includes a bore 64 that is sized to receive fasteners such as,for example, fixation pins, which may be utilized to secure the basecutting block 12 to the patient's femur. It should be appreciated thatin other embodiments the base cutting block 12 may include additionalfastener guides 62 or other fastening elements to secure the cuttingblock to the patient's femur. Each channel 60 of the block 12 is alignedwith one of the fastener guides 62 such that the bore 64 of the fastenerguide 62 opens into the channel 60.

As described above, the base cutting block 12 also includes a pair ofarms 42 that extend posteriorly from a posterior side 70 of the baseplate 40. Each arm 42 includes an articulating surface 72 shaped tomatch or correspond to a condylar surface of a femoral prostheticcomponent. In that way, the articulating surfaces 72 of the arms 42 areconfigured to contact a natural or prosthetic bearing surface of thepatient's tibia. The arms 42 are spaced apart such that an opening 74 isdefined therebetween.

The base cutting block 12 includes a number of cutting guides that maybe used during an orthopaedic surgical procedure to resect a portion ofa patient's femur. For example, as shown in FIG. 2, the base cuttingblock 12 includes a number of posterior cutting guides 76 defined in thearms 42 and a posterior chamfer cutting guide 78 defined in the baseplate 40. Each cutting guide 76, 78 includes an elongated slot sized toreceive a cutting saw blade of a surgical saw or other surgical device.In the illustrative embodiment, the posterior cutting guides 76 arepositioned to guide the resection of the posterior surfaces 628 (seeFIG. 24) of the distal end 622 of the patient's femur 620 when the basecutting block 12 is attached to the femur 620. The posterior chamfercutting guide 78 is positioned to guide the resection of the posteriorchamfer surfaces 630 of the distal end 622 of the patient's femur 620.

As described above, the system 10 also includes an offset guide assembly14 that may be secured to the base cutting block 12. As shown in FIG. 2,the system 10 includes a locking mechanism 80 configured to secure thebase cutting block 12 to the offset guide assembly 14. In theillustrative embodiment, the locking mechanism 80 includes a pair oflocking tabs 82, 84 pivotally coupled to the base cutting block 12. Eachof the locking tabs 82, 84 is coupled to the block 12 via a joint 86,which permits each of the locking tabs 82, 84 to pivot between a lockedposition (see tab 82) and an unlocked position (see tab 84). In theunlocked position, an ear 88 of the locking tab is positioned in anaperture 90 defined in the base plate 40 adjacent to the receiving slot52 of the base cutting block 12. In the locked position, the ears 88 arepositioned in the receiving slot 52 to thereby engage a mounting bracket92 of a surgical instrument such as, for example, a guide block 100 ofthe offset guide assembly 14 when positioned in the slot 52, asdescribed in greater detail below.

Returning to FIG. 1, the offset guide assembly 14 (hereinafter assembly14) includes the guide block 100 that may be coupled to the base cuttingblock 12 and an offset guide tool 102 configured to be secured to theintramedullary orthopaedic surgical instrument 16. In the illustrativeembodiment, the guide block 100 and the offset guide tool 102 are formedfrom metallic materials, such as, for example, stainless steel or cobaltchromium alloy. The guide block 100 includes a cylindrical passageway104 sized to receive a guide shaft 106 of the offset guide tool 102. Theassembly 14 also includes a locking mechanism 108 configured to securethe guide block 100 to the guide shaft 106, as described in greaterdetail below. In the illustrative embodiment, the guide block 100 andthe offset guide tool 102 are used with the intramedullary orthopaedicsurgical instrument 16 and the cutting block 12 to plan the reaming ofthe distal end 622 of the patient's femur 620. A surgical reamer 110,which is shown in FIG. 13 may be advanced over the guide shaft 106 toream and otherwise cut the distal end 622 of the patient's femur 620.

Referring now to FIGS. 4-7, the offset guide tool 102 includes the guideshaft 106 and a mounting shaft 120 attached to the guide shaft 106 via aconnecting body 122. As described in greater detail below, the guideshaft 106 may be pivoted relative to the mounting shaft 120. As shown inFIG. 4, the mounting shaft 120 of the tool 102 includes a proximal end124 and an opening 126 defined in the proximal end 124. An inner wall128 extends inwardly from the opening 126 to define a passageway 130extending through the mounting shaft 120. A plurality of internalthreads 30 are defined in the inner wall 128. As described above, theinternal threads 30 are configured to engage the external threads 28 ofthe stem trial 18, thereby securing the stem trial 18 to the guide tool102.

As shown in FIGS. 4-5, the guide shaft 106 includes a cylindrical body132 extending from a distal end 134 to a proximal end 136. A pluralityof external threads 138 are formed on the body 132 at the distal end134. As described in greater detail below, the external threads 138 areconfigured to engage a plurality of internal threads 140 of a handleassembly 280 (see FIG. 12) that may be used to pivot or rotate the guideshaft 106 relative to the mounting shaft 120. A plurality of slots 144are defined in the outer surface 146 of the cylindrical body 132. Eachslot 144 defines a desired attachment location of the guide block 100.As described in greater detail below, each attachment location of guideblock 100 corresponds to a number of different reaming depths. Aplurality of markings 148 are defined on the outer surface 146, and eachmarking 148 is associated with one of the slots 144 to indicate theattachment location to the user.

As shown in FIG. 6, an opening 150 is defined in the distal end 134 ofthe cylindrical body 132, and an opening 152 is defined in the oppositeproximal end 136 of the body 132. An inner wall 154 extends inwardlyfrom the opening 152 to an annular surface 156. The annular surface 156and the inner wall 154 cooperate to define a distal aperture 158 in thecylindrical body 132. Another inner wall 160 extends inwardly from theproximal opening 152 to define a passageway 162 that connects to thedistal aperture 158.

The connecting body 122 of the guide tool 102 includes a distal post 170that is positioned in the aperture 158 of the cylindrical body 132. Theconnecting body 122 is secured to the cylindrical body 132 via afastener (not shown) such as a pin or tab. In other embodiments, thecylindrical body 132 and the connecting body 122 may be secured via apress fit, taper fit, welding, or other fastening process. In theillustrative embodiment, the post 170 (and hence the connecting body122) is not permitted to rotate relative to the guide shaft 106.

The connecting body 122 of the guide tool 102 also includes a proximalsurface 172 and a proximal post 174 extending from the proximal surface172. As shown in FIG. 6, the proximal post 174 is offset from the distalpost 170 and is received in the passageway 130 defined in the mountingshaft 120. The post 174 is coupled to the mounting shaft 120 via a joint176 that permits relative movement between the mounting shaft 120 andthe connecting body 122 (and hence the guide shaft 106). In theillustrative embodiment, the joint 176 includes a locking ring 178 thatis received in annular slots 180 defined in the surfaces 182, 184 of thepost 174 and the mounting shaft 120, respectively. In that way, the ring178 retains the mounting shaft 120 on the post 174.

As shown in FIG. 6, the mounting shaft 120 has a longitudinal axis 190extending through its ends 124, 192. The cylindrical body 132 has alongitudinal axis 194 extending through its ends 134, 136 that extendsparallel to the longitudinal axis 190. In the illustrative embodiment,the axis 190 is offset from the axis 194 by approximately 4 millimeters,which matches the offset of the implant, as described in greater detailbelow. In other embodiments, the offset of the implant may greater thanor less than 4 millimeters. As described above, the mounting shaft 120is pivotally coupled to the guide shaft 106 via the connecting body 122.When the mounting shaft 120 is held fixed, the connecting body 122 andthe guide shaft 106 may be rotated about the longitudinal axis 190.Conversely, the mounting shaft 120 may be rotated about the longitudinalaxis 190 when the connecting body 122 or the guide shaft 106 is heldfixed.

As shown in FIGS. 6-7, the guide tool 102 also includes a lockingmechanism 200 configured to prevent relative rotation between themounting shaft 120 and the connecting body 122 (and hence the guideshaft 106). In the illustrative embodiment, the locking mechanism 200includes a rod 202 having a distal end 204 positioned in the passageway162 of the guide shaft 106. As shown in FIG. 6, the connecting body 122has a passageway 208 extending through the distal post 170, and the rod202 extends into the passageway 208.

A plurality of internal threads 210 are defined on the inner wall of theconnecting body 122, and a corresponding plurality of external threads212 are formed on a proximal end 214 of the rod 202. The rod 202 has atip 216 at the proximal end 214 that is received in a bore 218 definedin the connecting body 122. As shown in FIG. 6, the bore 218 has anopening 220 in the proximal surface 172, and an outer wall 222 of themounting shaft 120 is aligned with that opening 220.

The rod 202 may be rotated relative to the guide shaft 106 and theconnecting body 122 and thereby moved along the longitudinal axis 194between an unlocked position (see FIG. 6) and a locked position (seeFIG. 7). In the unlocked position, the tip 216 of the rod 202 is spacedapart from the outer wall 222 of the mounting shaft 120. When the rod202 is rotated in the direction indicated by arrow 224 in FIG. 6, thetip 216 is advanced into contact with the outer wall 222 of the mountingshaft 120, thereby preventing relative movement between the mountingshaft 120 and the connecting body 122 (and hence the guide shaft 106).

As described above, the offset guide assembly 14 also includes a guideblock 100 configured to be secured to the base cutting block 12.Referring now to FIGS. 8-10, the guide block 100 includes a mountingbracket 92 positioned at a proximal end 232 and a body 234 extendingfrom the bracket 92 to a distal end 236. As described above, themounting bracket 92 is configured to receive the locking tabs 82, 84 ofthe base cutting block 12. In the illustrative embodiment, the bracket92 includes a base 238 sized to be positioned in the receiving slot 52of the cutting block 12. As shown in FIG. 9, a channel 240 is defined ineach side 242 of the base 238. Each channel 240 is sized to receive oneof the ears 88 of the locking tabs 82, 84 when the tabs 82, 84 are inthe locked position and the base 238 is positioned in the receiving slot52. In that way, the guide block 100 may be secured to the cutting block12.

As shown in FIG. 10, a cylindrical passageway 104 extends through theends 232, 236 of the guide block 100. The cylindrical passageway 104 issized receive the guide shaft 106 of guide tool 102. As shown in FIG. 9,the body 234 of the guide block 100 has an elongated slot 242 definedtherein. The slot 242 connects to the passageway 104 and extendsparallel to the passageway 104.

As described above, the guide block 100 includes a locking mechanism 108configured to attach the block 100 to the guide shaft 106. In theillustrative embodiment, the locking mechanism 108 includes a pin orplate 252 positioned in a slot 254 defined in the body 234 of the block100. As shown in FIG. 10, the slot 254 (and hence the plate 252) extendstransverse to the passageway 104. The plate 252 includes an annular wall256, which defines a bore 258 sized to receive the guide shaft 106.

The locking mechanism 108 also includes a user-operated button 260 thatis attached to the plate 252. As shown in FIGS. 9-10, the user-operatedbutton 260 includes a contoured surface 262, which may be pressed tomove the plate 252 in the direction indicated by arrow 264 between alocked position and an unlocked position. In the locked position, a wallsection 266 of the plate 252 is positioned in the passageway 104; in theunlocked position, the bore 258 defined in the plate 252 is coaxial withthe passageway 104. In the illustrative embodiment, the lockingmechanism 108 includes a biasing element such as, for example, a spring268 positioned between the body 234 and the button 260 to bias the plate252 in the locked position.

In use, the distal end 134 of the guide shaft 106 is positioned belowthe proximal end 232 of the guide block 100 and aligned with thepassageway 104. The distal end 134 of the guide shaft 106 may beadvanced into the passageway 104. The button 260 may be pressed to movethe plate 252 to the unlocked position, thereby permitting the distalend 134 to advance through the bore 258 of the plate 252 and out of thepassageway 104.

One of the slots 144 defined in the outer surface 146 of the guide shaft106 may be aligned with the plate 252 to locate the guide block 100 in adesired position. As described above, each slot 144 has a marking 148associated with it to indicate the attachment location. When each slot144 is aligned with the plate 252, the marking 148 associated with thatslot 144 is visible through a window 270 extending transverse to theelongated slot 242. When the button 260 is released, the spring 268urges the plate 252 toward the locked position, thereby advancing thewall section 266 of the plate 252 into the selected slot 144. In thatway, the guide block 100 may be secured to the guide tool 102. When theguide block 100 and the cutting block 12 are secured to guide shaft 106,an oblique angle is defined between the proximal surface 46 of thecutting block 12 and the axis 194 of the guide shaft 106. It should beappreciated that in other embodiments the guide shaft may include only asingle slot or attachment location. In such embodiments, a number ofdifferent-sized guide blocks may be used to obtain the desired depth.

Referring now to FIGS. 11-12, a handle assembly 280 of the offset guideassembly 14 is shown. The handle assembly 280 is operable to rotate theguide shaft 106 relative to the mounting shaft 120 when the mountingshaft 120 is held fixed, such as, for example, when the mounting shaft120 is seated in the medullary canal of the patient's femur, asdescribed in greater detail below. The handle assembly 280 includes anelongated grip 282 and a central housing 284 extending away from thegrip 282. As shown in FIG. 11, the grip 282 and the housing 284 form theshape of a “T-handle.” It should be appreciated that in otherembodiments the handle assembly 280 may have a different configuration.The handle assembly 280 also includes a mounting tube 286 extending fromthe proximal end 288 of the housing 284 and a connecting shaft 290pivotally coupled to the mounting tube 286.

As shown in FIG. 12, the housing 284 has an opening 292 in the proximalend 288, and an inner wall 294 extends inwardly from the opening 292 toan annular surface 296. The inner wall 294 and the annular surface 296cooperate to define an aperture 298 in the housing 284. The mountingtube 286 of the handle assembly 280 extends from a distal end 300positioned in the aperture 298 to a proximal end 302. In theillustrative embodiment, the mounting tube 286 is secured to the housing284 via a cylindrical pin 304 such that relative movement between themounting tube 286 and the housing 284 is prevented. The handle assembly280 may be formed from a metallic material such as stainless steel,cobalt chrome, or titanium, although other metals or alloys may be used.Moreover, in some embodiments, rigid polymers such aspolyetheretherketone (PEEK) may also be used.

The mounting tube 286 has an opening 310 defined in the distal end 300,and an inner wall 312 extends inwardly therefrom to an annular surface314. The annular surface 314 cooperates with the wall 312 to define adistal passageway 316. The mounting tube 286 has another opening 318defined in the proximal end 302, and an inner wall 320 extends inwardlytherefrom to define a proximal passageway 322. As shown in FIG. 12,internal threads 140 are formed on the inner wall 320 adjacent to theproximal end 302. As described above, the internal threads 140 engagethe external threads 138 formed on the distal end 134 of the guide shaft106 to secure the handle assembly 280 to the offset guide tool 102.

As shown in FIG. 12, the connecting shaft 290 of the handle assembly 280extends through the passageways 316, 322. The connecting shaft 290includes a plug 324 and an elongated body 326 extending from the plug324. The elongated body 326 extends away from the plug 324 to a tip 330.The tip 330 is configured to engage the rod 202 of the locking mechanism200 such that the rod 202 may be moved between the locked and unlockedpositions. In the illustrative embodiment, the tip 330 is formed as ahex-head. As shown in FIG. 7, a corresponding socket 332 is defined thedistal end 204 of the rod 202.

Returning to FIG. 12, the plug 324 of the connecting shaft 290 has asocket 334 defined therein. The socket 334 is sized to receive a driverhead 702 of a surgical instrument 700, which may be used to rotate theconnecting shaft 290. The handle assembly 280 has a passageway 336 thatextends through the elongated grip 282 and is connected to the aperture298 defined in the housing 284. The passageway 336 is sized to permitthe passage of the driver head 702.

The handle assembly 280 also includes a biasing element such as, forexample, helical spring 338 to bias the plug 324 into engagement withthe annular surface 296 of the housing 284. In the illustrativeembodiment, the spring 338 is positioned between the plug 324 and theannular surface 314 of the mounting tube 286.

In use, the plug 324 of the connecting shaft 290 is initially positionedat the distal end 300 of the mounting tube 286 and engaged with thehousing 284. When the housing assembly 280 is secured to the distal end134 of the guide shaft 106, the driver head 702 may be advanced into thepassageway 336 and positioned in the socket 334 of the connecting shaft290. The plug 324 may be advanced along the distal passageway 316 of themounting tube 286 to advance the tip 330 into the socket 332 of the rod202. The connecting shaft 290 may then be rotated to move the rod 202from the unlocked position to the locked position or from the lockedposition to the unlocked position. When the rod 202 is moved to thedesired position, the driver head 702 may be withdrawn from theconnecting shaft 290. The spring 338 then urges the connecting shaft 290away from the rod 202.

Referring now to FIG. 13, the system 10 also includes a surgical reamer110. In the illustrative embodiment, the reamer 110 is a cannulatedreamer that is configured to be positioned on the guide shaft 106 toream a portion of the patient's intramedullary canal. The reamer 110includes an elongated body 352 including a shank 354 that fits into thechuck of a rotary power tool or a manual handle. In the illustrativeembodiment, the shank 354 is a Hudson end. It should be appreciated thatin other embodiments the shank may be configured to be received in achuck. The reamer 110 also includes a cutting head 356 located at theopposite, proximal end 358 of the body 352. The cutting head 356includes a plurality of helical cutting flutes 360. When the reamer 110is engaged with the patient's femur and rotated, the cutting head 356reams or otherwise cuts the bone tissue of the femur.

The reamer 110 has an opening 362 defined in the proximal end 358 of theelongated body 352. A cylindrical inner wall 364 extends inwardly fromthe opening 362 to an inner surface 366. The cylindrical inner wall 364and the inner surface 366 cooperate to define an aperture 368 sized toreceive the distal end 134 of the guide shaft 106. In that way, theguide shaft 106 may be used to guide the reamer 110 to ream or otherwisecut the bone tissue of the femur.

The reamer 110 may be constructed from a metallic material such asstainless steel, cobalt chrome, or titanium, although other metals oralloys may be used. Moreover, in some embodiments, rigid polymers suchas polyetheretherketone (PEEK) may also be used.

The reamer 110 includes a number of depth marks 370, 372, 374 formed onits elongated body 352 at a location above the cutting head 356. Each ofthe depth marks 370, 372, 374 corresponds to a predetermined reamingdepth that is required to implant the revision femoral prosthesis 650.During a surgical procedure, the reamer 110 is advanced over the guideshaft 106 deeper into the intramedullary canal of the patient's femuruntil the desired depth mark aligns with the distal surface of thepatient's femur. In such a way, over-reaming of the distal end of thecanal is avoided if the reamer 110 is not driven beyond the appropriatedepth mark.

Referring now to FIG. 14, an orthopaedic surgical instrument construct400 of the system 10 is shown. The construct 400 includes the basecutting block 12, the intramedullary orthopaedic surgical instrument 16,and an intramedullary adaptor 402 configured to be coupled to the basecutting block 12 and the intramedullary orthopaedic surgical instrument16. As shown in FIG. 14, the intramedullary orthopaedic surgicalinstrument 16 includes the stem trial 18 and a stem stabilizer 404having a proximal end 406 secured to the stem trial 18 and a distal end408 configured to be secured to the adaptor 402.

The stem stabilizer 404 is formed from a metallic material, such as, forexample, a stainless steel or a cobalt chromium alloy. In otherembodiments, the stabilizer 404 may be formed from a rigid polymer suchas, for example polyetheretherketone (PEEK) may also be used. Thestabilizer 404 includes a cylindrical body 410 having a centralpassageway 412 defined therein. In the illustrative embodiment, thecylindrical body 410 is devoid of any fins or projections. It should beappreciated that in other embodiments the stem stabilizer may includefins or projections to provide additional stability within the medullarycanal.

As shown in FIG. 15, a cylindrical inner wall 414 defines the passageway412. A plurality of internal threads 418 are formed on the inner wall414, which are configured to engage a plurality of external threads 416formed on the adaptor 402. As such, the stabilizer 404 may be threadedonto the adaptor 402 to secure the stem stabilizer 404 to the adaptor402. The internal threads 418 of the stem stabilizer 404 also correspondto the external threads 28 formed on the stem trial 18 such that thestem trial 18 may be threaded onto the stem stabilizer 404 to assemblethe intramedullary surgical instrument 16. When the intramedullarysurgical instrument 16 is assembled as shown in FIG. 14, the stem trial18 and the stem stabilizer 404 cooperate to define a longitudinal axis420 of the intramedullary surgical instrument 16.

The stem stabilizer 404 also includes a pair of channels 422, 424defined in the distal end 408. The channel 422, 424 extends from theouter surface of the stabilizer 404 to the passageway 412. The innerwall 414 includes a pair of arced sections 426, 428 of the inner wall414 that extend between the channels 422, 424. The arced sections 426,428 are substantially smooth.

As described above, the construct 400 includes an intramedullary adaptor402 configured to be secured to the base cutting block 12. What is meantherein by the term “intramedullary adaptor” is a surgical toolconfigured to be secured to an intramedullary orthopaedic surgicalinstrument and including an end sized and shaped to be positioned in amedullary canal of a patient's femur during the orthopaedic surgicalprocedure. As shown in FIGS. 16-17, the intramedullary adaptor 402includes a mounting bracket 440 and a proximal adaptor body 442. Anintermediate adaptor body 444 is pivotally coupled to the proximaladaptor body 442 and the mounting bracket 440, as described in greaterdetail below. Similar to the mounting bracket 92 of the guide block 100,the mounting bracket 440 is configured to receive the locking tabs 82,84 of the base cutting block 12. In the illustrative embodiment, thebracket 440 includes a base 446 sized to be positioned in the receivingslot 52 of the cutting block 12. As shown in FIG. 16, the base 446includes a pair of arms and a channel 240 is defined in each arm. Eachchannel 240 is sized to receive one of the ears 88 of the locking tabs82, 84 when the tabs 82, 84 are in the locked position and the base 446is positioned in the receiving slot 52. In that way, the intramedullaryadaptor 402 may be secured to the cutting block 12.

As shown in FIG. 16, the mounting bracket 440 includes a central housing448 that extends proximally from the base 446. The central housing 448and the intermediate adaptor body 444 cooperate to define a longitudinalaxis 450 of the intramedullary adaptor 402, as shown in FIG. 17. Anotherlongitudinal axis 452 that extends parallel to the axis 450 is definedby the proximal adaptor body 442. In the illustrative embodiment, theaxis 452 is offset from the axis 450 by 4 millimeters, which matches theoffset of the implant, as described in greater detail below. In otherwords, the axes 450, 452 of the adaptor 402 are offset by the samedistance as the axes 190, 194 of the offset guide tool 102.

As shown in FIG. 17, the mounting bracket 440 of the adaptor 402 hassubstantially planar distal surfaces 454, 456. The surfaces 454, 456cooperate to define an imaginary plane 458 that extends transverse tothe longitudinal axis 450. In the illustrative embodiment, an obliqueangle 460 is defined between the axis 450 and the imaginary plane 458.In the illustrative embodiment, an oblique angle 460 is defined betweenthe axis 450 and the imaginary plane 458, and the magnitude of the angle460 matches the angle of the implant.

The proximal adaptor body 442 of the adaptor 402 has a distal end 470coupled to the intermediate adaptor body 444 and a proximal end 472configured to be secured to the orthopaedic intramedullary surgicalinstrument 16. As shown in FIG. 16, the proximal end 472 of the proximaladaptor body 442 includes a plurality of external threads 416 thatengage the internal threads 418 of the stem stabilizer 404. The proximaladaptor body 442 has a contoured outer surface 474 adjacent to thedistal end 470 and a passageway 476 that extends inwardly from anopening 478 defined in the proximal end 472.

As shown in FIG. 18, an opening 480 is defined in the opposite distalend 470 of the adaptor body 442. An inner wall 482 extends inwardly fromthe opening 480 to define a distal aperture 484 in the adaptor body 442.The proximal passageway 476 opens into the distal aperture 484 and, asshown in FIG. 18, is sized to receive a cylindrical rod 486. The rod 486extends into an aperture 488 defined in the intermediate adaptor body444, as described in greater detail below.

The intermediate adaptor body 444 of the adaptor 402 includes a proximalsurface 490 and a proximal post 492 extending from the proximal surface490. As shown in FIG. 18, the aperture 488 is defined in the proximalpost 492, and the proximal post 492 is configured to be received in thedistal aperture 484 defined in the proximal adaptor body 442. In theillustrative embodiment, the post 492 is coupled to the adaptor body 442via a joint 496 that permits relative movement between the adaptorbodies 442, 444. In the illustrative embodiment, the joint 496 includesa locking ring 498 that is received in annular slots 500 defined in thewalls 482, 504 of the post 492 and the adaptor body 442, respectively.In that way, the ring 498 retains the adaptor body 442 on the post 492.

The intermediate adaptor body 444 of the adaptor 402 also includes adistal post 510 that is offset from the proximal post 492. As shown inFIG. 18, the distal post 510 has an opening 512 defined its end 514, andan inner wall 516 extends inwardly from the opening 512 to an annularsurface 518. The wall 516 and the surface 518 cooperate to define adistal aperture 520 in the distal post 510. In the illustrativeembodiment, internal threads 522 are formed on the inner wall 516. Theinternal threads 522 are configured to engage an externally-threadedinsert 524, as described in greater detail below.

An inner wall 526 extends inwardly from the annular surface 518 todefine a bore 528 in the adaptor body 444. As shown in FIG. 18, the bore528 has an opening 530 defined in the proximal surface 490 of the body444. In the illustrative embodiment, internal threads 532 are formed onthe inner wall 526. The internal threads 532 are configured to engage anexternally-threaded pin 534, as described in greater detail below.

As shown in FIG, 18, the mounting bracket 440 has an opening 540 definedin the central housing 448. An inner wall 542 extends inwardly from theopening 540 to an annular surface 544, and another inner wall 546extends from the annular surface 544 to an opening 548 defined in thebase 446 of the mounting bracket 440. The inner walls 542, 546 and theannular surface 544 cooperate to define a passageway 550 extendingthrough the mounting bracket 440.

The proximal section 552 of the passageway 550 is sized to receive thedistal post 510 of the adaptor body 444. In the illustrative embodiment,the post 510 is coupled to the mounting bracket 440 via a joint 554 thatpermits relative movement between the mounting bracket 440 and theadaptor body 444 (and hence the adaptor body 442). In the illustrativeembodiment, the joint 554 includes a locking ring 556 that is receivedin annular slots 558 defined in the walls 542, 560 of the mountingbracket 440 and the post 510, respectively. In that way, the ring 556retains the mounting bracket 440 on the post 510.

As described above, the intermediate adaptor body 444 of the adaptor 402is pivotally coupled to the proximal adaptor body 442 and the mountingbracket 440 via joints 496, 554. As such, when the proximal adaptor body442 is held fixed, the intermediate adaptor body 444 (and hence themounting bracket 440) may be rotated about the longitudinal axis 452.Conversely, the proximal adaptor body 442 may be rotated about the axis452 when the intermediate adaptor body 444 is held fixed. Additionally,when the mounting bracket 440 is held fixed, the intermediate adaptorbody 444 (and hence the proximal adaptor body 442) may be rotated aboutthe longitudinal axis 450. Conversely, the mounting bracket 440 may berotated about the axis 452 when the intermediate adaptor body 444 isheld fixed.

In the illustrative embodiment, the adaptor 402 includes a distallocking mechanism 570 configured to prevent relative movement betweenthe intermediate adaptor body 444 and the mounting bracket 440. Theadaptor 402 also includes a proximal locking mechanism 572 configured toprevent relative movement between the intermediate adaptor body 444 andthe proximal adaptor body 442. As shown in FIG. 18, the distal lockingmechanism 570 includes the threaded insert 524, which has a head 574 anda threaded shaft 576 extending from the head 574. A passageway 578extends through the head 574 and the shaft 576—that is, the passageway578 extends through the length of the threaded insert 524.

As shown in FIG. 19, the head 574 of the insert 524 is positionedbetween the annular surface 544 of the mounting bracket 440 and alocking ring 580 secured to the inner wall 542 of the mounting bracket440. The threaded shaft 576 of the insert 524 engages the internalthreads 522 of the distal post 510 of the adaptor body 444. In theillustrative embodiment, rotation of the insert 524 about the axis 490causes the intermediate adaptor body 444 to move between an unlockedposition (see FIG. 19) and a locked position (see FIG. 20).

In the unlocked position shown in FIG. 19, relative movement between theadaptor body 444 and the mounting bracket 440 is permitted. When theinsert 524 is rotated about the axis 490 in the direction indicated byarrow 582 in FIG. 19, the insert 524 engages the locking ring 580, whichprevents the insert 524 from moving proximally such that the distal post510 of the adaptor body 444 is drawn distally along the axis 490, asindicated by arrow 584. As the distal post 510 is advanced along theaxis 490, the distal post 510 engages the locking ring 580 and anannular flange 586 of the adaptor body 444 engages the central housing448, as shown in FIG. 20. The engagement between the annular flange 586of the body 444 and the central housing 448 prevents movement betweenthe adaptor body 444 and the mounting bracket 440. The engagementbetween the post 510 and the locking ring 580 also assists in preventingmovement between the adaptor body 444 and the mounting bracket 440.

As shown in FIGS. 19-20, the head 574 of the insert 524 has a socket 590defined therein. The socket 590 is sized to receive a driver head 702 ofa surgical instrument 700. When the driver head 702 is received in thesocket 590, the instrument 700 may be used to rotate the insert 524 andthereby operate the locking mechanism 570.

As described above, the adaptor 402 also includes a proximal lockingmechanism 572 configured to prevent relative movement between theintermediate adaptor body 444 and the proximal adaptor body 442. Asshown in FIGS. 21-22, the locking mechanism 572 includes the threadedpin 534. The pin 534 has a threaded plug 592 and an elongated shaft 594extending from the plug 592. The threaded plug 592 of the pin 534engages the internal threads 532 of the adaptor body 444. In theillustrative embodiment, rotation of the pin 534 about the axis 490causes the pin 534 to move between an unlocked position (see FIG. 21)and a locked position (see FIG. 22). The pin 534 includes a socket 596configured to receive a driver head (not shown), which may be advancedthrough the passageway 578 of the threaded insert 524.

In the unlocked position, the elongated shaft 594 of the pin 534 ispositioned in the bore 528 of the adaptor body 444 and is spaced apartfrom the distal end 470 of the proximal adaptor body 442 such thatrelative movement between the intermediate adaptor body 444 and theproximal adaptor body 442 is permitted. When the pin 534 is rotated, theelongated shaft 594 is advanced proximally along the bore 528 and intoengagement with the distal end 470 of the proximal adaptor body 442. Theengagement between the pin 534 and the proximal adaptor body 442prevents movement between the adaptor bodies 442, 444.

Returning to FIG. 14, the base cutting block 12 is configured to becoupled to a plurality of modular cutting blocks. A number of modularcutting blocks suitable for use with the base cutting block 12 are shownand described in U.S. patent application Ser. No. 13/485,470 entitled“FEMORAL ORTHOPAEDIC SURGICAL INSTRUMENTS AND METHOD OF USE OF SAME,”which is incorporated herein by reference. The system 10 includes alocking or retention mechanism 600 that secures each modular cuttingblock to the base cutting block 12. In the illustrative embodiment, theretention mechanism 600 includes a pair of mounting brackets 602attached to the base cutting block 12 and a corresponding pair ofmounting brackets attached to each modular cutting block. The system 10also includes a cover 604 (see FIG. 38), which may be positioned overthe mounting brackets 602 of the base cutting block 12 when none of themodular cutting blocks are secured to the base cutting block 12.

Referring now to FIG. 23, a revision femoral orthopaedic prosthesis 650for use in the performance of an orthopaedic knee replacement procedureis shown. The prosthesis 650 includes a femoral component 652 and a stemcomponent 654 that may be secured to the femoral component 652. Thecomponents 652, 654 may be constructed with an implant-gradebiocompatible metal, although other materials may also be used. Examplesof such metals include cobalt, including cobalt alloys such as a cobaltchrome alloy, titanium, including titanium alloys such as a Ti6Al4Valloy, and stainless steel. Such a metallic components may also becoated with a surface treatment, such as hydroxyapatite, to enhancebiocompatibility. Moreover, the surfaces of the metallic components thatengage the natural bone may be textured to facilitate securing thecomponents to the bone. Such surfaces may also be porous coated topromote bone ingrowth for permanent fixation.

The femoral component 652 is configured to be implanted into asurgically-prepared distal end 622 of the patient's femur 620, and isconfigured to emulate the configuration of the patient's natural femoralcondyles. As such, the lateral condyle surface 656 and the medialcondyle surface 658 are configured (e.g., curved) in a manner whichmimics the condyles of the natural femur. The lateral condyle surface656 and the medial condyle surface 658 are spaced apart from one anotherthereby defining an intercondylar notch therebetween.

The condyle surfaces 656, 658 are positioned opposite a proximal surface660. The femoral component 652 also includes an elongated stem post 662,extending superiorly away from the proximal surface 660. The elongatedfemoral stem post 662 is configured to receive the stem component 654.

As shown in FIG. 23, the component 654 includes an elongated body 664that extends from a head 668. The head 668 is shaped to be received inan aperture (not shown) defined in the stem post 662. The prosthesis 650includes a fastener (not shown) to secure the stem component 654 to thefemoral component 652. The fastener may include a taper fit between thehead 668 and the stem post 662, a threaded fastener, or other fasteningdevice.

The elongated body 664 of the stem component 654 has a longitudinal axis670 that is offset from and extends parallel to a longitudinal axis 672of the stem post 662. As shown in FIG. 23, an oblique angle is definedbetween each of the axis 670, 672 and the proximal surface 660. Themagnitude of that angle in the illustrative embodiment is 5 degrees. Inthe illustrative embodiment, the axis 670 is offset from the axis 672 byapproximately 4 millimeters. It should be appreciated that in otherembodiments the offset may be greater than or less than 4 millimetersdepending on the patient's bony anatomy. In the illustrative embodiment,the stem component 654 may be secured to the femoral component 652 atany orientation relative about the axis 672 of the stem post 662. Inthat way, the elongated body 664 of the stem component 654 may be offsetfrom the stem post 662 in any orientation about the axis 672.

The prosthesis 650 also includes an offset indicator 680 configured toindicate the offset orientation between the stem component 654 and thefemoral component 652. In the illustrative embodiment, the offsetindicator 680 includes a marking 682 defined on the stem post 662 and aplurality of markings 684 defined on the body 664 of the component 654.Each marking 684 corresponds to a different offset orientation. Asdescribed in greater detail below, the markings 682, 684 of the offsetindicator 680 correspond to markings formed on the offset guide assembly14 and the instrument construct 400, respectively, such that thosesurgical instruments may be used to determine intraoperatively thedesired offset orientation of the prosthesis 650.

As shown in FIGS. 24-39, the system 10 may be utilized during theperformance of an orthopaedic surgical procedure to implant the femoralprosthesis 650 in a distal end 622 of a patient's femur 620. The offsetguide assembly 14 may be utilized to plan and guide the reaming of thepatient's femur 620 with the surgical reamer 110, as shown in FIGS.24-32. As shown in FIGS. 33-34, the surgical reamer 110 forms a chamber624 in the distal end 622 of the patient's femur 620. The chamber 624 isconnected to the medullary canal 626 of the patient's femur 620 and issized to receive the stem post 662 of the femoral component 652 and theproximal end of the stem component 654. As shown in FIGS. 35-39, theinstrument construct 400 may be inserted into the chamber 624 and themedullary canal 626 and a gap assessment may be performed to determineand set femoral rotation. The construct 400 may be used to beginresecting and shaping the distal end 622 of the patient's femur 620,including the posterior surfaces 628 and the posterior chamfer surface630, to receive the femoral prosthetic component 652.

Prior to inserting the offset guide assembly 14, an orthopaedic surgeonmay remove a prior prosthetic implant and drill and/or ream themedullary canal 626. Multiple drills or reamers may be used to formand/or increase the size of a distal opening 632 of the medullary canal626 of the patient's femur 620. When the reaming operation is complete,the medullary canal 626 is configured as shown in FIG. 24.

The surgeon may utilize the offset guide assembly 14 may be utilized todetermine intraoperatively a desired offset orientation of theprosthetic stem component 654 relative to the stem post 662 of thefemoral component 652. To do so, the surgeon may select a stem trial 18and secure the selected stem trial 18 to the offset guide tool 102. Thestem trial 18 may be selected from a plurality of different sized stemtrials 18. The stem trials may vary in length, diameter, or otheraspect, and the surgeon may select the stem trial 18 based on thepatient's anatomy and the type of prosthetic stem component to beincluded in the femoral prosthesis.

After selecting the stem trial 18, the surgeon may attach the stem trial18 to the mounting shaft 120 of the offset guide tool 102. To do so, thesurgeon may align the distal end 24 of the stem trial 18 with thepassageway 130 of the shaft 120. The surgeon may then advance the distalend 24 into the passageway 130. As described above, a plurality ofexternal threads 28 are formed on the stem trial 18, and the threads 28engage the internal threads 30 formed on the mounting shaft 120. Assuch, the stem trial 18 may be threaded into the mounting shaft 120,thereby securing the stem trial 18 to the guide tool 102. As shown inFIG. 24, the assembled stem trial 18 and the guide tool 102 may bealigned with and advanced into the distal opening 632 of the medullarycanal 626 of the patient's femur 620.

When seated in the medullary canal 626, the guide tool 102 may becoupled to the guide block 100 of the offset guide assembly 14. As shownin FIG. 25, the guide block 100 may be first secured to the base cuttingblock 12. To do so, the mounting bracket 92 of the guide block 100 ispositioned in the receiving slot 52 of the base cutting block 12. Asurgeon may use a driver or other surgical tool to rotate the lockingtabs 82, 84 as indicated by arrows 640 in FIG. 25. As the locking tabs82, 84 are rotated, the ears 88 are advanced into the correspondingchannels 240 defined in the mounting bracket 92, thereby securing theblocks 12, 100 together.

The surgeon may then advance the assembled blocks 12, 100 over thedistal end 134 of the guide shaft 106. Alternatively, the surgeon maychoose to attach the guide block 100 to the base cutting block 12 afterattaching the guide block 100 to the guide shaft 106. To secure theguide block 100 to the guide shaft 106, the guide block 100 (and hencecutting block 12) is positioned such that the passageway 104 is alignedwith the distal end 134 of the guide shaft 106. The surgeon may depressthe button 260 on the guide block 100 to move the locking plate 252 tothe unlocked position and advance the guide block 100 over the distalend 134 of the guide shaft 106.

As shown in FIG. 26, the assembled blocks 12, 100 may be advancedproximally along the shaft 106 to align the block 100 with one of theslots 144 defined in the shaft 106. As described above, each slot 144defined on the shaft 106 corresponds to a different reaming depth, andthe surgeon may select the slot 144 corresponding to the reaming depthrequired for the selected prosthesis 650. The surgeon may utilize thewindow 270 defined in the guide block 100 to read the marking 148associated with each slot 144 to identify the slot corresponding to thedesired reaming depth. When the marking 148 associated with the selectedslot 144 is positioned in the window 270, the surgeon may release thebutton 260 to permit the locking plate 252 to advance into the selectedslot 144 and thereby secure the blocks 12, 100 to the guide shaft 106.

The surgeon may then attach the handle assembly 280 to the distal end134 of the guide shaft 106, as shown in FIG. 27. To do so, the proximalpassageway 322 of the handle assembly 280 is aligned with the distal end134 and advanced over the distal end 134. The handle assembly 280 may berotated relative to the guide shaft 106 such that the internal threads140 of the handle assembly 280 engage the external threads 138 formed onthe distal end 134 of the guide shaft 106 to secure the handle assembly280 to the offset guide tool 102.

When the handle assembly 280 is secured to the guide shaft 106, thesurgeon may utilize the handle assembly 280 to identify the desiredoffset orientation of the prosthesis 650. To do so, the surgeon may gripthe elongated grip 282 of the handle assembly 280 to rotate the grip 282(and hence the guide shaft 106) as indicated in FIG. 27 by arrow 642. Asthe grip 282 is turned, the guide shaft 106 of the guide tool 102 isrotated relative to the stem trial 18 and the mounting shaft 120 aboutthe longitudinal axis 22 of the stem trial 18. Because the blocks 12,100 are attached to the mounting shaft 120, the blocks 12, 100 arerotated with mounting shaft 120.

When viewed in a transverse plane defined by the distal surfaces 634 ofthe femur 620, as shown in FIGS. 28-29, the longitudinal axis 194 of theguide shaft 106 is moved along an elliptical path 644. That movementchanges the position of the cutting block 12 on the distal end 622 ofthe patient's femur 620. The surgeon may continue to turn the grip 282until the cutting block 12 is placed in a location on the patient'sfemur 620 that offers maximum coverage of the distal end 622. When thecutting block 12 is in the desired location on the patient's femur 620,the surgeon may utilize an offset indicator 686 on the offset guideassembly 14 to identify the selected offset orientation.

As shown in FIGS. 28-29, the offset indicator 686 includes a pluralityof markings 688 defined on the proximal surface 690 of the guide block100. Each marking 688 corresponds to a different offset orientation. Inthe illustrative embodiment, the markings 688 include lines and, in someembodiments, numerical indicators that are associated with the lines toidentify the offset orientations. The offset indicator 686 also includesa marking 694 (see FIG. 5) on the guide shaft 106. When the marking 694is aligned with one of the marking lines 688, the surgeon may identifythe line 688 to determine the offset orientation.

When the cutting block 12 is in the desired location on the patient'sfemur 620, the surgeon may lock the guide shaft 106 in position relativeto the mounting shaft 120. To do so, a driver head 702 of a surgicalinstrument 700 may be advanced into the passageway 336 of the handleassembly 280, as shown in FIG. 30. With the driver head 702 positionedin the socket 334 of the connecting shaft 290, the connecting shaft 290is advanced along the distal passageway 316 of the handle assembly 280into the passageway 162 of the guide shaft 106 and engagement with therod 202 of the guide tool locking mechanism 200.

The connecting shaft 290 may then be rotated to move the rod 202 fromthe unlocked position to the locked position. As described above, whenthe rod 202 is in the locked position, the tip 216 of the rod 202engaged with the outer wall 222 of the mounting shaft 120, therebypreventing relative movement between the mounting shaft 120 and theconnecting body 122 (and hence the guide shaft 106). When the rod 202 isin the locked position, the driver head 702 may be withdrawn from theconnecting shaft 290 and the blocks 12, 100 detached from the guideshaft 106.

The surgeon may then ream the distal end 622 of the patient's femur 620to the desired reaming depth. As shown in FIG. 31, the aperture 368 ofthe reamer 110 may be aligned with the distal end 134 of the guide shaft106. The reamer 110 may then be advanced over the guide shaft 106 andinto engagement with the distal end 622 of the femur 620. The reamer 110may be attached to a rotary source such as, for example, a surgicaldrill configured to rotate the reamer 110. When rotated, the cuttingflutes 360 of the reamer 110 engage the femur 620 to remove materialfrom the bone. The surgeon may advance the reamer 110 proximally alongthe shaft 106 until one of the depth marks 370, 372, 374 of the reamer110 is aligned with distal surfaces 634 of the patient's femur 620, asshown in FIG. 32. As described above, the depth mark is selected basedon the reaming depth required to implant the revision femoral prosthesis650. After advancing the reamer 110 to the desired depth, the reamer110, the guide tool 102, and the stem trial 18 may be removed from thedistal end 622 of the patient's femur 620.

As shown in FIGS. 33-34, the reaming operation forms a chamber 624 inthe distal end 622 of the patient's femur 620. The chamber 624 isconnected to the medullary canal 626 of the patient's femur 620 and issized to receive the stem post 662 of the femoral component 652 and theproximal end of the stem component 654. As shown in FIG. 34, the chamber624 has a longitudinal axis 694 that is offset from the anatomical axis696 of the medullary canal 626. An oblique angle 698 is defined betweenthe axis 694 and an imaginary plane defined by the distal surfaces 634of the patient's femur 620.

After reaming the distal end 622 of the patient's femur 620, the surgeonmay assemble the instrument construct 400 and insert the intramedullaryorthopaedic surgical instrument 16 into the chamber 624 and themedullary canal 626 of the patient's femur 620. To assemble theconstruct 400, the surgeon selects a stem stabilizer 404 from aplurality of stem stabilizers, including stem stabilizers that havefins. The stem stabilizer may be selected based on the patient's anatomyand whether additional stability may be needed in the patient's femur620. When the surgeon has selected an appropriate stem stabilizer 404,the surgeon may thread the stem trial 18 onto the stem stabilizer 404 toform the intramedullary orthopaedic surgical instrument 16 shown in FIG.35.

To secure the intramedullary orthopaedic surgical instrument 16 to theintramedullary adaptor 402, the passageway 412 of the stem stabilizer404 is aligned with the proximal end 472 of the adaptor 402. The stemstabilizer may then be advanced over the proximal end 472 and threadedonto the adaptor 402. The engagement between the threads 416, 418 of theadaptor 402 and the stabilizer 404, respectively, secures the stabilizer404 to the adaptor 402.

The intramedullary adaptor 402 may be then attached to the base cuttingblock 12. To do so, the mounting bracket 440 of the adaptor 402 ispositioned in the receiving slot 52 of the base cutting block 12. Asurgeon may use a driver or other surgical tool to rotate the lockingtabs 82, 84. As the locking tabs 82, 84 are rotated, the ears 88 areadvanced into the corresponding channels 240 defined in the mountingbracket 440, thereby securing the adaptor 402 to the block 12. Thesurgeon may choose to attach the adaptor 402 to the base cutting block12 before attaching the intramedullary orthopaedic surgical instrument16 to the adaptor 402.

The surgeon may then configure the adaptor 402 to position theintramedullary orthopaedic surgical instrument 16 in the desired offsetorientation. To do so, the surgeon may utilize an offset indicator 710defined on the adaptor 402. In the illustrative embodiment, the offsetindicator 710 includes a marking 712 defined on the intermediate adaptorbody 444 and a plurality of markings 714 defined on the proximal adaptorbody 442. Each marking 714 corresponds to one of the markings 684 on theprosthesis 650 and hence to a different offset orientation of theprosthesis 650. In the illustrative embodiment, the marking 712 isarrow-shaped, and the markings 714 include lines and, in someembodiments, numerical indicators associated with the lines to identifythe offset orientations. When the marking 712 is aligned with one of themarking lines 714, the surgeon may identify the line 714 to determinethe offset orientation.

As described above, the desired offset orientation is determined priorto the reaming operation using the offset guide assembly 14. The surgeonmay locate the line 714 on the proximal adaptor body 442 correspondingto the offset orientation identified using the offset guide assembly 14and rotate the intermediate adaptor body 444 (and hence the mountingbracket 440) relative to the proximal adaptor body 442 to align themarking 712 with the identified line 714. As described above, when theproximal adaptor body 442 is held fixed, the intermediate adaptor body444 (and hence the mounting bracket 440) may be rotated about thelongitudinal axis 452 of the proximal adaptor body 442.

When the intermediate adaptor body 444 is in the desired orientationrelative to the proximal adaptor body 442 (and hence the intramedullaryorthopaedic surgical instrument 16), the surgeon may operate theproximal locking mechanism 572. To do so, the surgeon advances a driverhead through the mounting bracket into the socket 196 defined in thelocking pin 534. When the pin 534 is rotated, the elongated shaft 594 ofthe pin 534 is advanced proximally along the bore 528 defined in theadaptor body 444 and into engagement with the distal end 470 of theproximal adaptor body 442. The engagement between the pin 534 and theproximal adaptor body 442 prevents movement between the adaptor bodies442, 444, thereby locking the adaptor bodies 442, 444 in the desiredoffset orientation.

After the instrument construct 400 is assembled, the surgeon may insertthe intramedullary orthopaedic surgical instrument 16 into the chamber624 and the medullary canal 626 of the patient's femur 620. To do so,the surgeon aligns the stem trial 18 of the intramedullary orthopaedicsurgical instrument 16 with the chamber 624 and advances the instrumentconstruct 400 into the patient's femur 620, as shown in FIGS. 35-36. Amallet or other surgical tool may be used to drive the intramedullaryorthopaedic surgical instrument 16 deeper into the patient's bone to theposition shown in FIG. 36.

As shown in FIGS. 37-39, the surgeon may then assess the gap definedbetween the cutting block 12 and a tibial component 720 such as, forexample, a prosthetic tibial tray or tibial tray trial. To do so, thesurgeon may insert the driver head 702 of the surgical instrument 700into the adaptor 402 to engage the socket 590 of the distal lockingmechanism 570. The surgeon may rotate the driver head 702 in thedirection indicated in FIG. 37 by arrow 722 to rotate the insert 524 anddisengage the annular flange 586 of the adaptor body 444 from thecentral housing 448 of the adaptor 402. In that way, the mountingbracket 440 and the base cutting block 12 may be permitted to rotaterelative to the intramedullary orthopaedic surgical instrument 16. Thesurgeon may also attach the cover 604 to the base cutting block 12 tocover the mounting bracket 602, as shown in FIG. 37.

The surgeon may assess the flexion and extension gaps through the rangeof motion. To do so, the surgeon may utilize a gap assessment tool 730to perform the assessment. An exemplary gap assessment tool is shown anddescribed in U.S. patent application Ser. No. 13/485,470 entitled“FEMORAL ORTHOPAEDIC SURGICAL INSTRUMENTS AND METHOD OF USE OF SAME,”which is incorporated herein by reference.

As shown in FIG. 38, a gap 740 is defined between the base cutting block12 and a tibial trial component 720 attached to a patient's tibia 724.With the patient's knee in flexion as shown in FIG. 38, the surgeon mayinsert the gap assessment tool 730 into the gap 740. The surgeon maymove the knee between flexion (FIG. 38) and extension (FIG. 39) toevaluate the gap 740 and the stability of the construct throughout therange of motion. The surgeon may adjust the thickness of the assessmenttool 730 to achieve desired gap geometry. It should be appreciated thatin other embodiments the gap assessment may be performed with anothertype of tensioning device, such as, for example, a laminar spreader.

The surgeon may also consider the femoral rotation of the base cuttingblock 12. To do so, the surgeon may balance the base cutting block 12parallel to the tibial component 720 at 90 degrees of flexion as shownin FIG. 38. The surgeon may grasp the side walls 54 of the base cuttingblock 12 to rotate the base cutting block 12 in the direction indicatedby arrows 750 until the gap 740 defined between the base cutting block12 and the tibial component 720 is rectangular. When the base cuttingblock 12 is balanced, the surgeon may use the driver head 702 to operatethe distal locking mechanism 570 to secure the intramedullary adaptor402 to the intramedullary orthopaedic surgical instrument 16, therebypreventing relative movement between the mounting bracket 440 and thebase cutting block 12 and the instrument 16.

When the instrument construct 400 is properly positioned relative to thedistal end 622 of the patient's femur 620, the surgeon may proceed withfurther resections to shape the distal end 622 to receive the prostheticfemoral component 652. To do so, the surgeon may attach one or moremodular cutting blocks to the base cutting block 12. The surgeon mayalso use the cutting guides 76, 78 to guide posterior and chamfer cutsof the distal end 622 of the patient's femur 620.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. A method of positioning a femoral cutting block, the methodcomprising: coupling an offset adaptor assembly to the femoral cuttingblock such that an opening in the femoral cutting block is aligned witha first longitudinal axis, coupling a stem stabilizer to the offsetadaptor assembly such that the stem stabilizer extends along a secondlongitudinal axis, coupling a stem trial to the stabilizer such that thestem trial extends along the second longitudinal axis, positioning thestem stabilizer and the stem trial in a cavity defined in a distal endof a patient's femur such that the stem stabilizer and the stem trialare prevented from rotating about the second longitudinal axis, andmoving the femoral cutting block relative to the distal end of thepatient's femur to position the femoral cutting block for resecting thedistal end, wherein moving the femoral cutting block includes rotatingthe femoral cutting block about the first longitudinal axis and thesecond longitudinal axis.
 2. The method of claim 1, wherein rotating thefemoral cutting block about the first longitudinal axis and the secondlongitudinal axis includes rotating an intermediate body of the offsetadaptor assembly about the first longitudinal axis and the secondlongitudinal axis while a proximal body of the offset adaptor assemblyis prevented from rotating.
 3. The method of claim 2, wherein couplingthe stem stabilizer to the offset adaptor assembly includes securing thestem stabilizer to the proximal body.
 4. The method of claim 2, furthercomprising inserting a surgical tool through the opening defined in thefemoral cutting block into a cavity of the intermediate body thatextends along the first longitudinal axis.
 5. The method of claim 1,wherein coupling the offset adaptor assembly to the femoral cuttingblock includes positioning a mounting bracket in the opening defined inthe femoral cutting block.